This invention relates to apparatus for use with an upstanding sewer pipe riser or drain to facilitate the attachment of a toilet bowl outlet and associated sealing gasket. Specifically, the invention relates to a collar which maintains an annular space about the riser or drain during pouring of a concrete floor.
During the construction of buildings, plumbing pipes are normally partially installed, i.e., roughed in, prior to the completion of the floors and walls of the building. Thereafter, concrete floors are poured about the roughed in pipes, including upright risers designed to sealingly engage, for example, a toilet bowl outlet and associated sealing gasket. Unless an annular space is provided about the riser, connection of the riser to an appliance such as a toilet bowl is extremely difficult and, as a result, the concrete immediately surrounding the riser must be broken away.
Attempts have been made in the past to solve this problem by providing devices designed to maintain an annular space about the riser during the pouring of a concrete floor. For example, see U.S. Pat. No. 3,421,551 issued Jan. 14, 1969. This patent describes the use of a destructable foam plastic sleeve fitted about a riser. After pouring the floor, the sleeve is compressed and broken away with a tool such as a screwdriver to establish an annular cavity about the upper end of the riser.
The present invention relates to an improved device for maintaining an annular space about a drain pipe riser during the pouring of the concrete (or other) material floor. Specifically, the present invention in one exemplary embodiment includes a collar having an outer substantially cylindrical sleeve and an inner substantially cylindrical sleeve, the two sleeves being concentrically arranged and radially spaced from each other. The sleeves are temporarily held together by a plurality of "knock-out" fingers or webs which are secured between the inner and outer sleeves at both the upper and the lower ends of the sleeves. In the exemplary embodiment, the webs are arranged in a multiplicity of V-shaped configurations where adjacent webs are joined together on the interior surface of the outer sleeve, and are secured at circumferentially spaced locations on the exterior surface of the inner sleeve.
A knock-out cap or plate is provided at the upper end of the collar, covering the entire opening defined by the outer sleeve. The joints between the webs and sleeves are relatively weak, permitting the webs to be knocked-out to thereby enable separation of the inner and outer sleeves after the floor has been poured. The cap or plate is removable in a similar manner, and is utilized principally to prevent the inadvertent admission of wet concrete into the riser.
It will be appreciated by those of ordinary skill in the art that the drain collar disclosed herein can be produced in many different sizes for use with virtually any diameter riser. In a preferred arrangement, the entire collar including the inner and outer sleeves as well as the webs extending therebetween are constructed as a one-piece plastic collar.
It will be further appreciated by those of ordinary skill in the art that after the installation of the collar over the upright riser, a concrete floor may be poured, an annular space being reserved between the concrete and the riser, corresponding to the radial space between the inner and outer sleeves. Once the concrete has set, the knock-out webs and cap or plate may be broken away from the outer sleeve so that the inner sleeve and webs may be removed, leaving the outer sleeve adhered to the set concrete, and a well defined annular space surrounding the riser.
In accordance with one exemplary embodiment of the invention, therefore, the drain collar of this invention comprises an inner, substantially cylindrical sleeve adapted to fit over an upper open end portion of a drain riser; an outer, substantially cylindrical sleeve radially outwardly spaced from the inner sleeve; and a plurality of webs extending between the inner and outer sleeves to maintain a peripheral space of predetermined width therebetween.
Additional objects and advantages of the invention will become apparent upon consideration of the detailed discussion of the invention which follows.